American Sign Language: "lucky"
/ "luck"

The sign for lucky touches the tip of your middle finger (bent
forward at the large knuckle) to your chin and then twists the hand
towards the front. (Don't try to twist it all the way toward the
front -- just to a comfortable angle then stop otherwise you'll be
unlucky and have joint problems.)

LUCKY

LUCKY (animation)

If you want to say "good luck" to someone, sign "good" and then spell luck.
Notice how the fingerspelling of luck is very quick and uses abbreviated
handshapes:

GOOD-LUCK:

Good luck (animation)

Notes:
A student asks: Is the difference between "delicious" and "lucky" the starting position of
the "8" finger?

Response:
Yes, one of the The differences between lucky and delicious
is the starting position.
LUCKY starts on the chin.
DELICIOUS (at least one of the variations of the sign "delicious") starts on
the lips. DELICIOUS has other variations though -- including a version
that snaps the middle finger off of the thumb as you move the hand
from the mouth up into the air.